There are thought to be less than 250 adult Northwest African or Saharan cheetahs, making the subspecies critically endangered, but very little is known about the cat.

The first camera-trap photographs of the cheetah, taken as part of a systematic survey of 1,750 square miles of the central Sahara, are providing scientists with information on population numbers, movement and how it interacts with its environment.

The cheetah is found across the Sahara desert and savannah of north and west Africa in small, fragmented populations, the biggest of which is thought to be in Algeria.

The survey identified four different Saharan cheetahs by examining the pattern of their spots, which are unique to each individual animal.

The research also provided photographic confirmation of the presence of sand cats in the region and, through the collection of a horn, confirmation that the scimitar-horned oryx - now extinct in the wild - had once lived in the area.

Dr Sarah Durant, senior research fellow with ZSL, said: "The Saharan cheetah is critically endangered, yet virtually nothing is known about the population, so this new evidence, and the ongoing research work, is hugely significant."

Farid Belbachir, research student at ZSL and research fellow at the Universite de Bejaia in Algeria who is implementing the survey said: "This is an incredibly rare and elusive subspecies of cheetah and current population estimates, which stand at less than 250 mature individuals, are based on guesswork.

"This study is helping us to turn a corner in our understanding, providing us with information about population numbers, movement and ecology."

The research was undertaken by ZSL, Office du Parc National de l'Ahaggar and the Universite de Bejaia, with support from the Wildlife Conservation Society and Panthera, an organisation dedicated to conserving the world's 36 species of wild cat.